Material for magnetic apparatus and process of making same



Jan. 1, 1929. y 1,697,142

L. H. ROLLER j MATERIAL FOR MAGNETIC APPARATUS ANDPROCESS F MAKING'SAMFiled Nov. 21, 1925 Patented Jan. 1, 1929.

UNITED STATES PATENT OFFICE.

LOUIS H.. ROLLER, F WHITE PLAINS, NEW YORK..

MATERIAL ron MAGNE'rIc Arrana'rns AND :enocnss or MAKING SAME.,

Application led November "211925. Serial No. 70,687.

is mechanically strong, Water proof, gas" anon-conductor of highreluctance to but proof and in the main, electricity and offering a thepassage of magnetic lines of.v force,

having therein clearly nagnetic reluctivity.

It is a' well known practice to pass magnetic lines of force through thewalls of a sealed Container to container instead of transmitting powerby means of moving mechanical elements passing through the wall with theconsequent danger of leakage around suchv elements. However, in order toavoid serious losses due to eddy currents, such walls must be made ofelectrically non-conducting mate-,

rial. On the other hand this has heretofore limited one to the use ofmaterials that have a high magnetic reluctance, have had to be Very thinto avoid serious losses due to leakage of magnetic fiux.

It is' an object of the present invention to provide a material whichovercomesl these objections by providing a material which is not subjectto appreciable eddy current losses, in which a low magnetic reluctanceis pro'- vided Where desired, and which, therefore,A

will provide a wall ofconsiderable thickness Without entailing materiallosses due to magnetic leakage. l

A specific use of my improved material will be found in my co-pendingapplication, Se- .rial No. 710,680, filed May 2, 1924:, which describedan electro-magnetic pump in which magnetic lines of force were passedthrough a sealed cylinder into an armature to reciprocate the latter andin which the cylinder was made of non-metallic material containing zonesof low reluctance formed by embedding soft iron particles in thematerial.

It will be obvious that there would be many other-uses to which thematerial could be applied, in certain of which it would be desirable notto form the material in cylinders but to form it in other shapes.-Furthermore, if formed in cylinders certain uses would require that theregions of low reluctance be arranged transversely to the axis of thecylinder while in other cases the regions of low reluctance shouldbearranged parallel to the axis of the cylinder.

defined paths of low,V

perform work within the.

s that the walls In producing the material I employ a woven fabric ofclothy in which fine threads of soft iron orV other metal of highmagnetic permeability are interwoven, the wire forming stripes in thelmpregnated with certain well knownphenol condensation products andbuilt up to any desired thickness by coiling it or piling it in layerswith the, stripes superposed. Thereafter the coil or pile is subjectedto a heat and pressure to form a bakelite orcondensite mass in which thewires are embedded'.

I am aware'that it is not new to lembed vmetallic'wires in bakelite orcondensite, a

patent on' such material having been Agranted to John Taylor, December12, 1922, No. 1,438,875. However, the material described cloth. Thecloth is-then in said patent was designedwith'an entirely differentpurpose in View, viz,that of strength so that the material could be usedfor gears and similar mechanical elements. Such material would beentirelyl unsuitable for my purpose, uniformly distributed throughoutthe material and must necessarily be so distributed for-the purpose ofgiving uniform strength. But it will be evident that while such materialwould reduce the magnetic reluctivity such magnetic qualities would beuniformly distributed through the material and would defeat the purposefor which I intend-to use my material. For the purpose I have in view'itisessential that deiined regions of low magnetic reluctance should beprovided and that these regions beseparated by regions of highreluctance otherwise 'there wouldbelittle advantage in using thematerial disclosed by Taylor cited, over that of using a continuoussheet or tube of'iron. It is therefore, an objectof my inventiontoprovide avmaterial in which the regions of low reluctance areseparated by regions of high reluctance Wit no physical joint betweenvsuch regions.

I also believe that I am the first to produce "a fabric With separatestripes of iron wlre woven therein Heretofore, metallic wires have beeninterwoven with threads of tex-4 tile material but the materialcontainedwires running lengthwlse as well as transversely to the material and wasnot confined to mate-A 'having stripes of wire running in one direcvbecause the metallic strands are tion only and to provide an eicientprocess for making suchY a fabric.

Thesrt and other objects I attain as hereinafter set forth, referencebeing had to the accompanying drawings in which Figure l is adiagrammatic perspective viewot' a piece of fabric provided with threadsof soft metal interwoven with nonmetallir threads;

Fig. 2 is an edge view of a sheet of my improved material showing theiron wires arranged in layers vertically alincd;

Fig. 3 is a view similar to Fig. 2 representing a. modified form of mymaterial in which the layers ot' iron wires are arranged in staggeredrelation to form inclined paths of low reluctance through tlnl material;

Fig. 'i illustrates one application of my material showing inlongitudinal cross aection a fragmentary view of a magnetically operatedpump having a cylinder of my improved materlal. the pump being similarin form to that disclosed in the aforesaid eopendingr application;

Fig. 5 represents another application of my material illustrating arotary motor of induction type in which the armature of the motor isenclosed in a casing formed of my improved material, the viewrepresenting a longitudinal section through a fragment of the. casingwith the armature of the motor indicated by broken lines;

Fig. 6 is a cross sectional view taken on the line l--t ot' Fig. 5: and

Fig. T is a diagrammatic plan view of anothermodification of my materialillustrating how a plurality of spots of high magnetic permeability maybe formed with angularly disposed layers of fabric.

Referring to Fig. l, it will be observed that the fabric of which mymaterial is composed has a warp of textile threads 10 displaced atintervals by metallic threads 11, while the weft threads 1;.' are all oftextile material.

.As the object of this fabric is no-t to attain physical strength butmagnetic permeability in defined regions the wires are preferably asfine as the textile threads. In practice it has been found inadvisableto use a. large number of wire strands in the warp wit-hout intei-posingoccasionally one or more textile threads between the wires. Because ofthe smoothness and hardness of the metallic strands the matting actionwhich is desirable in weaving is absent, and there is a tendency for thefilling threads to slide out between the warp threads while shedding. Inother words, after the weft threads have been beaten into the shed bythe reed, there is a tendency for the filling to slide out during theshedding operation, that is, during the raising and lowering ofalternate` warp strands. i This is prevented, however, by inioducing athread of textile material between the wire warp threads. In practice itis found that desirable matting can be obtained if one or more threadsof textile material be introduced between every four or five metallicthreads. I therefore, form the warp with stripes of metallic wiresinterspersed with textile threads as shown at 13 in Fig. 1. It will beunderstood of course, that the' stripe of iron wire need not be confinedto the number shown in the drawing but may extend over any desired widthof the fabric provided warp threads of' textile material are introducedat sufiicientl frequent intervals to produce the desireclmatting of thefabric. Having produced the fabric shown in Fig. 1 the next step of myprocess is to impregnate the fabric with a phenolic condensationproduct, after which layers of fabric are arranged in a pile as shown inFig. 2 with the stripesof metallic wire in superposed alined relation.The fabric may be arranged in a flat pile or may be Wound in a coil toform a solid rod or it may be wound around a form, if it be desired, toproduce a cylindrical, rectangular or other form. The pile of fabric isthen subjectedto pressure and heat and the condensation product fillsthe spaces between the textile threads and between the wires inseparablybinding all parts together in a uniform hard substance in which wire isthoroughly embedded. The material is very strong and shows no tendencyto cleavage between regions of high reluctance and low reluctance. Thematerial is also water proof and gas proof and a good electricalinsulator except where the wire provides a path for electric currentand. because the wire strands are separated by the textile threads andthe impregnating condensite product, a high resistance to electriccurrent is offered, which tends in use to prevent the formation of eddycurrents. At the same time the magnetic reluctance of the material ismarkedly lowered in the zones or regions traversed by the Wires.

As explained above one of the. principal uses for which this material isadapted is to be found in the art of refrigeration in which itisdesirable to have a closed system sealed against gas leakage and inwhich mechanical work may be performed by means of energy transmittedfrom without the system,

avoiding any moving member passing into.

the system. Such au application was described in the aforesaidco-pending application and is illustrated in Fig. 4. lt comprises a pumpemploying a cylinder 16 formed of my improved material, having thereinZones 17 of low magnetic reluctance runningcireumferentially about thecylinder. The. cylinder is surrounded by field coilsA 18 located incomb-shaped yokes 19, the teeth of'whieh engage thc zones 17. Within thecylinder 16 is a pump plunger :2l carri/ul b v a vtio i the lines ofmagnetic flux passing between,

and tightly secured by means of wedges 26.'

Although condensite and bakelite are generally considered to beinsoluble, I have found that they are not insoluble inl anhydrous ammonia and hence, it is desirable to line the cylinder w1th somematerial, such for in l stance, as tin, which is not affected by ammonia when my pump is to be used for pumping ammonia gas. Such a lineris indicated at 27 and as it is not required to have any great strength,because the cylinder itself is strong enough to resist any pressuresdeveloped by the pump, it may be made merely thick enough to preventactual contact of any liquid ammonia with the bakelite or condensitesurface. The liner may be applied to the cylinder electrolytically or inany other suitable manner and as its purpose is merely to rovide a.coating non-soluble in the fiuids handled by the pump it need notnecessarily be of meta-l. But if a metal liner be used it should benon-magnetic so as not -to divert the yoke 19 and the armatures 23,through the zones 17. Because the material of which the cylinder iscomposed o'ers considerable reluctance to the passage of magnetic linesof force, an easier path for the flux is found through the zones 17 intoand out of the armatures 23, and because of the thinness'of the liner2.7 there is no' appreciable loss due to leakage of iux. It will beunderstood of course, that when the pump is to be used for pumping othergases or liquids which do not affect my improved material the liner 27may be dispensed with.

While I have illustrated my improved-material as employed with areciprocating pump, it will be evident that it can also be used with anysolenoid or an straight line motor. Fig. 5 illustrates anot erapplication in which the material is employed in connection with a rtarymotor. The ligure shows a cross sectional view of an induction motorwith the armature removed but indicated by broken lines at 30. The fieldwindings 31 and core 32 are separated from the armature by a casing 33of my improved material in which bearings (one being indicated at 34)are provided for the armature shaft 35. A construction such as this canbe used in refrigerating apparatus to provide rotary motion within asealed casing transferring energy through the walls of the casingwithout any mechanical transmission of motion through the casing'. Inthis application of'my material, however, the regions of low magneticreluctance must not run circumferentially` about the casing but must runparallel to the axis of the armature, otherwise there would be amagnetic short circuit between the field poles and little or'no magneticflux would reach the armature. Instead the lines of lo'w magneticreluctance run lengthwise-of the cylindrical casing 33 as indicated at36. In building up a.

casing of this sort, itwill be evident that care ,m'ustbe exercised toarrange the layers of fabric so that'the wire stripes of the outerlayers will be wider than those of the inner layers,A thus forming thesector shaped regions illustrated in the cross sectional view of Fig. 6.In forming the fabric it will be nece-ssary to compute the number-ofwires required to effect this result. l In other words, the stripes ofmetal must be progressively wider across the width'of the fabric andmust be separated bysuccessively wider stripes of non-metallic fabric asWe proceed from the inner to the outer layers. It is possible to arrangethe warp of the fabric with considerable accuracy so thatthe successivelayers will fall one above the other as the fabric is Wound widthwiseabout a form. However, while it is desirable that the zones of lowmagnetic reluctance be de cessfuluse of m'y material.A For instance,there could be and in commercial practice doubtless would be,considerable irregularity along the margins of the zones, provided theprincipal object is maintained of producing a patlof much lowerreluctance through the material into the armaturethan exists betweensuccessive fields of poles, so that by far a greater part of themagnetic energy will ypass into the armature instead of leaking acrossfrom one pole 'to` another. It will be ed transversely by radial lines,this resul isnot essential to the suc-v lll() noted that the thicknessof the casing is much thickness but this material is machined down orotherwise reduced aloner the zones or re-` gionswhere the wire isembeddedyso as to reduce the thickness at these points as much aspossible and thereby reduce the magnetic reluctance. At these pointsnot-only is the material reinforced by thewire therein, but it is alsolreinforced by the pole pieces which bear against the wire zones, so thatthe cylinder is not materially weakened by/ such reduction of thickness.c

I have described the fabric of which my material is composed as havingwire stripes running lengthwise or' in the warp material. In pcommercialpractice it is simpler to Weave a frabric with wire strands in the warprather than in the fwefts, but it would be possible and in certain'easespreferable to use wire-in the weft rather than in the warpl and hence Ido`not limit myself to a fabric with wire warp strands.

I have referred to the fact that it is not esof thev of the nextadjacent layer in building up my material. Indeed in some cases I findit desirable to offset the successive layers somewhat, so as to obtainthe result shown in Fig. 3 wherein the paths of low reluctance through.the material, are inclined instead of being `normal to the plane of thematerial.

Another modication .is illustrated' diagrammatically in Fig. 7 whichshows the wire stripes of a plurality of layers of fabric, the body ofthe fabric being omitted. Three layers of stripes 11', 112 and 113 areindicated, each layer forming an angle of 60 degrees with the other two.When the material is made up of layers so disposed there will beintersecting spots where the magnetic reluctance is but one third ofthat through other parts of the material traversed by the stripes. Thematerial may be' built up of any number of layers thus angularlydisposed and smaller angular displacements may be used to further reducethe relative reluctivity at isolated spots. In fact the layers may eachbe provided with a single stripe or even a single wire and thesuccessive layers be assembled with a minute angular displacement abouta common intersecting point, when the transverse path of low reluctivityat such point will have a relative reluctance value inverselyproportional yto the number of the angles of displacement.

I claim:

1. A material for use in magnetic apparatus consisting of a solidifiedplastic substance having layers of textile fabric embedded therein, thefabric being formed with interwoven stripes of soft iron wire.

2. A material for use in magnetic apparatus consistingpf a series offabric layers b ound together by a solidified phenolic condensationproduct, each layer including a -stripe of magnetizable strands woveninto the fabric.

3. A material for use in magnetic apparatus consisting of a series offabric layers bound together by4 a solidified phenolic condensationproduct, each layer including a stripe of highly para-magnetic metalwoven into the fabric.

4. A material for use in magnetic apparatus consisting of a series offabric layers bound together by a solidified phenolic condensationproduct, each layer including a stripe of soft iron wire Woven into thefabric.

5. A material for use in magnetic apparatus consistingr of a series offabric layers` bound together by a solidified phenolitI condensationproduct, each layer including a stripe of low reluctance wire Woven intothe fabric, the stripes being superposed and alined.

6. A material for use in magnetic apparatus consisting of a series offabric layers bound together with a solidified phenolic condensationproduct, and each layer including.,r a stripe of lo` reluctance wireWoven into the fabric. the stripe of each layer being disposed in apre-determined geometrlc relation to the stripes of adjacent layers.

7. A material for use in magnetic apparatus consisting of a series offabric layers bound together by a solidified phenolic condensationproduct and each layer including a stripe of iron wire woven into thefabric, said stripes being disposed in superposed relation, and aprotective coating von the surface of the material.

8. A material for use in magnetic apparatus consisting of a series offabric layers bound together by a solidified phenolic condensationproduct and each layer including a stripe of iron wire woven into thefabric, said stripes being disposed in superposed relation, and a'non-magnetic metallic coating on the surface of the material.

9. A cylinder for use in a magnetic apparatus consisting of a length offabric having a stripe of iron wire woven therein, the fabric beingspirally wound to form a coil and the whole being bound together by asolidified phenolic condensation product.

10. A cylinder for use in magnetic apparatus consisting of a hollowcylindrical coil of fabric bound by a solidified phenolic condensationproduct, the fabric including a circumferentially disposed stripe ofiron woven into the fabric.

11. A cylinder for use in amagnetic apparatus consisting of a length offabric having a stripe of iron wire woven therein, the fabric beingspirally Wound to form a hollow cylindrical coil and the whole beingbound together by a solidified phenolic condensation product, and aprotective coating on the inner surface of the cylinder.

12. The process of making material for magnetic apparatus which consistsin weaving a fabric of textile material With stripes of metal threadsinterwoven therein, impregnating the fabric with a phenolic condensationproduct, arranging the vfabric in layers with the stripes in superposedand alined relation, and subjecting the whole to heat and pressure.

1E. The process of making material for magnetic apparatus which consistsin impregnating textile fabric with a phenolic condensationproduct, thefabric having stripes of metal interwoven therein, arranging thefabriclin layers with the stripes of each layer disposed in apre-determined geometric relation to the stripes of adjacent layers, andsubjecting the Whole to heat and pressure to solidify the phenoliccondensation product.

14. The process of making material for magnetic apparatus which consistsin impregnating textile fabric having stripes 0f metal interwoventherein, with a phenolic condensation product, arranging the fabric 1nlayers with the stripes of the several layers dlsposed to superposed andalined relallU Laenge tion, and subjecting .the wholev to heat andpressure.

15. The process of making material for 'magnetic apparatus whichconsistsin im 5 pre ating with a phenolic condensation pro uct a textile fabrichaving stripes of metal interwoven therein, winding the fabric about aform with the stripes of metal in the several coils of the windingdisposed in superv posed and alined relation, and subjecting-the.

whole to heat and pressure.'

v16. A material for use in magnetic apparatus yconsisting of asolidified plastic substance having layers- 'of textile fabric embeddedtherein, the fabric being formed with .inter- 'v voven stripes ofmagnetizable material.V

LOUIS H. ROLLER. 1

